<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>边框</title>
    <style>
        .box{
            width: 600px;
            height: 800px;
            border: 2px rgb(69, 57, 55) dashed;
            margin: 0 auto;
        }
        .box ul li{
            list-style: none;
            float: left;
            margin: 0 10px;
            padding: 5px 10px;
            border-right: 1px solid red;
        }
        .box .padd{
            height: 300px;
            font-size: 50px;
            border: 2px solid rgb(0, 115, 255);
            padding: 20px 30px;
        }
        table{
            border-collapse: collapse;
        }
    </style>
</head>
<body>
    <table border="1">
    <tr>
        <td>123</td>
        <td>123</td>
        <td>123</td>
        <td>123</td>
    </tr>
    <tr>
        <td>123</td>
        <td>123</td>
        <td>123</td>
        <td>123</td>
    </tr>
    <tr>
        <td>123</td>
        <td>123</td>
        <td>123</td>
        <td>123</td>
    </tr></table>
    <div class="box">
        <ul>
            <li>1</li>
            <li>2</li>
            <li>3</li>
        </ul>
        <p class="padd">内边距</p>
    </div>
</body>
</html>